In certain instances, it is important to provide box containers which have top flaps that can be fully opened to lay flat against the outside of the box. In particular, automated filling machinery may have narrow passages for such boxes. Flaps that extend outward from the box may get caught in such machinery.
Paperboard boxes can be formed to have flaps that lay flat. However, for plastic corrugated boxes, the plastic in the score lines between the flaps and the side walls has memory that causes the flaps to spring back. This causes the flaps to move back toward a planar relationship with the side walls.
The present invention provides an improved score line for use with plastic corrugated boxes.